vboot: vb2_shared_data offsets should hang off parentstabilize-12428.B

vb2_shared_data struct has many offsets to other objects in the
workbuf.  They are all prefixed with `workbuf_`, e.g.:
  uint32_t workbuf_data_key_offset;
  uint32_t workbuf_data_key_size;

In order to adhere to a hierarchical structure on the workbuf,
remove the workbuf_ prefix from these symbols to reflect the
relationship between vb2_shared_data and its children more
accurately.

Create a helper function vb2_member_of to safely look up a child
of a particular object in the workbuf by offset.  Pointer
arithmetic to find vb2_shared_data children is replaced with
calls to this function.

BUG=b:124141368, chromium:994060
TEST=make clean && make runtests
BRANCH=none

Change-Id: Ia82417a35d2067ee5e4f42fea0396e6325127223
Signed-off-by: Joel Kitching <kitching@google.com>
Cq-Depend: chromium:1753400
Reviewed-on: https://chromium-review.googlesource.com/c/chromiumos/platform/vboot_reference/+/1718264
Commit-Queue: Joel Kitching <kitching@chromium.org>
Tested-by: Joel Kitching <kitching@chromium.org>
Reviewed-by: Julius Werner <jwerner@chromium.org>

1 files changed, 9 insertions, 0 deletions

diff --git a/firmware/2lib/include/2common.h b/firmware/2lib/include/2common.h
index f0df9c0b..ccc0bfc4 100644
--- a/firmware/2lib/include/2common.h
+++ b/firmware/2lib/include/2common.h
@@ -166,6 +166,15 @@ vb2_error_t vb2_align(uint8_t **ptr, uint32_t *size, uint32_t align,
 ptrdiff_t vb2_offset_of(const void *base, const void *ptr);
 
 /**
+ * Return member of given object.
+ *
+ * @param parent	Pointer to parent object
+ * @param offset	Offset from base
+ * @return Pointer to child object.
+ */
+void *vb2_member_of(void *parent, ptrdiff_t offset);
+
+/**
  * Return expected signature size for a signature/hash algorithm pair
  *
  * @param sig_alg	Signature algorithm